SHARMA CLASSES BHARATPUR

  Our Environment Ecosystem: An ecosystem is a self-contained unit of living things (plants, animals and decomposers), and their non-living environment (soil, air and water). For example; a forest, a pond, a lake, a green land etc. ·          In an ecosystem, energy and matter are continuously exchanged between living and non living components. ·          An ecosystem can be both natural or man-made. Some examples of natural ecosystems are grass land, forest, sea, river, desert, mountain, pond, lake etc. ·          The desert, grass land and mountains represent the terrestrial ecosystem (land-based ecosystem). ·          The ponds, rivers, lakes and sea represent the aquatic ecosystem (water-based ecosystem). Man-made artificial ecosystems are garden, crop fields, park, aquarium, etc. Components of Ecosystem: There are two components of an ecosystem : (i) biotic component and (ii) abiotic component. 1. Biotic component: It includes three types of organisms : (a) Produce

  HEREDITY Heredity:  It refers to the transmission of characters or traits from the parents to their offspring. Heredity is the continuity of features from one generation to another which are present in fertilized egg or zygote. The zygote develops into an organism of a particular type only. Genetics:  It is the branch of biology which deals with heredity and variation. Genetics is to help our understanding of heredity by knowing how offspring inherit characteristics from their parents. Variation :  It means the differences in the characters or traits among the individuals of a species. Variations occur during reproduction both because of error in DNA copying and as a result of sexual reproduction. Variations contribute to evolution. There are two types of variation- somatic variation and gametic variation. Importance of variations ·          It is the basis of the heredity. ·          It is the basis of the evolution also. ·